ellipsis()
  overflow:hidden
  white-space:nowrap
  text-overflow: ellipsis

bg-image($url)
  background-image:url("images/"+$url+"@2x.png")
  background-repeat: no-repeat
  @media (-webkit-min-device-pixel-ratio:3),(min-device-pixel-ratio:3)
    background-image:url("images/"+$url+"@3x.png")